The first goal of the study was to examine the very long term effects of early cumulative risk over and above any effects of early intervention and to learn whether early intervention and early risk interacted when predicting the selected outcomes. As previously reported (Campbell et al. 2008
), for the combined Abecedarian and CARE samples, early educational intervention was significantly associated with educational attainment in general, attending a four year college or university specifically, and obtaining skilled employment. The present analyses showed, in addition, that a prospective measure of cumulative risk summed across the first five years of life negatively predicted overall educational attainment, high school graduation specifically, and being employed as a young adult. Unexpectedly, early intervention was not found to moderate associations between early risk and young adult outcomes within this sample.
The second goal of this study was to examine a moderated mediation hypothesis: whether the quality of the early home mediated the found effects of early cumulative risk on later outcomes and whether early educational intervention moderated the effects of the early home environment on these outcomes. The results suggest that the home environment did mediate the effects of early risk for high school graduation but not for being employed or teen parenthood. Support for the moderated mediation hypothesis was found only for education attainment in general: the early home environment appeared to mediate the association between early risk and this outcome for the control group but not the treated group.
The present study found associations between early risk and young adult accomplishments, a longer time span than is typical in the literature. The finding that early risk significantly predicted overall educational attainment and high school graduation specifically confirms as well as extends earlier work showing increased early cumulative risk to be associated with poor concurrent and shorter-term academic outcomes (Brody, Kim & Murry, 2003
; Forehand, Biggar & Kochick, 1998
; Gutman, Sameroff & Cole, 2003
; Gutman, Sameroff & Eccles, 2002
; Prelow & Loukas, 2003
). The finding that higher early risk was associated with an increased likelihood of teen parenthood adds to previous work showing how individual risk factors are associated with teen parenthood (Cairns & Cairns, 1994
; Haveman, Wolfe & Wilson, 1997
; Ludtke, 1997
; Miller-Johnson, Winn, Coie, Malone & Lochman, 2004
). The current finding is modified by the fact that, within this sample, teen parenthood was no longer significantly predicted by risk when models simultaneously examined early risk, the early home environment, and early treatment.
The present findings suggest that when early cumulative risk and intensive early education in a child care setting are considered simultaneously, higher level accomplishments in young adulthood were affected by early educational intervention while more basic level accomplishments were associated with early risk. High school graduation, being employed as a young adult, and teen parenthood were all predicted by early cumulative risk irrespective of early intervention, whereas going to college and having a skilled-level job in young adulthood were predicted by early treatment, irrespective of early risk. Perhaps early risk added little to the prediction of going to college because it was at the earlier stage of completing high school that risk did the most harm, precluding the possibility of going to college. This is consistent with the report by Teachman, Paasch, Day, and Carver (1997)
that family poverty appears to exert its greatest impact on high school graduation rather than on college attendance. Thus, within a high-risk sample, those experiencing the higher levels of risk find it harder to achieve some of the basic accomplishments of young adulthood, such as graduating from high school or getting any job. Early intervention, on the other hand, may provide the boost needed for higher levels of success, such as attending college or obtaining skilled employment.
A key finding from the present analyses is that treatment moderated the mediation of risk through the quality of the home environment. This effect emerged when predicting to the linear measure of young adult education attainment. For children in the control group, early cumulative risk was associated with a poorer quality home environment which in turn was associated with lower levels of education attainment in young adulthood. This was consistent with our hypotheses. In contrast, our analyses found no evidence of such mediation for the treated group. Having the five years of educational intervention in a high quality child care setting appeared to be protective, that is, it buffered treated children against the long-term effects of a poor quality early home environment on later educational attainment. This finding is consistent with other work suggesting that early intervention may moderate the effects of the early home environment (Bradley et al., 2001
). Previous research involving the effects of child care on shorter term outcomes with high-risk samples has found evidence that child care quality serves as a protective factor for some outcomes but not others. Burchinal et al. (2006)
in their study of African-American children in kindergarten through third grade found quality child care to be protective for math scores and behavior problems, but not for reading. Thus, different protective factors may be important for different outcomes (Gutman, Sameroff, & Cole, 2003
). The results here suggest that the effect for treatment was larger for those from poor quality home environments than for those from higher quality early home environments. This implies that high quality child care may be more effective for children whose parents are less responsive and provide less stimulating home environments than for other children.
While evidence was found that early home environment mediated the effects of risk for educational outcomes, no evidence of such mediation was found for being employed or teen parenthood. The HOME, the measure used to assess the quality of the early home environment, has previously been shown to be associated with cognitive development and academic outcomes (Bradley, Caldwell, & Rock, 1988
). Given this, its association with later educational outcomes in the present sample is consistent with the literature. One mechanism to explain the significant mediation findings is suggested by the work of Brody, Kim, and Murry (2003)
who studied young African-American adolescents growing up in single-mother homes in rural settings. These investigators found that cumulative risk was associated with parenting practices, which were in turn associated with youth self-regulation. Self-regulation was in turn associated with academic achievement. Heckman, Stixrud, & Urzua (2006)
have suggested that noncognitive factors, as well as cognitive factors, strongly predict educational attainment. The environment provided by one’s parents, combined with inherited ability and early intervention all play a role (Heckman et al., 2006
). However, in the present study, the links between the early home environment and later educational attainments appear to be different from those that influence being employed and adolescent parenthood. The decision to become sexually active is complex (Michels, Kropp, Eyre, & Halpern-Felsher, 2005
). Concurrent peer relationships and other adolescent circumstances undoubtedly play crucial roles in decisions made about parenthood when an adolescent is faced with such a life-altering experience. Young adult employment is subject to concurrent employment opportunities as well as personal characteristics influencing one’s desire to seek work. Thus, the effects of early cumulative risk on employment and teen parenthood outcomes need further study; the links may be direct, as found here, or mediated through other early or concurrent factors not assessed in this study.
The hypothesis that increased early risk would be positively associated with illegal activity was not confirmed within this sample. In the present study, crime was represented by the young adults’ self-reported convictions for misdemeanors and felonies and use of illegal drugs. A large body of research links risk and concurrent behavior problems. For example, using an index of cumulative risk, Furstenberg, Cook, Eccles, Elder, and Sameroff (1999)
found that urban adolescents with 8 or more risk indicators (out of 10 possible) showed a 40% rate of behavior problems, compared to only 7% of those with 2 risk factors. However, these authors were examining current rates of problem behavior compared with current risk circumstances. Perhaps concurrent risk is more predictive of these outcomes than cumulative risk experienced much earlier in the life span.
No evidence was found that early educational intervention and early risk directly interacted to influence young adult outcomes. This finding was unexpected. It is noteworthy in this regard that the present sample consisted entirely of individuals who were drawn from high risk backgrounds. Whether children exposed to more risk gain more from quality child care is a research question pertinent to policies regarding preferential entrance into public child care programs, such as Head Start and pre-kindergarten, many of which use a high risk index to determine who is recruited. Prior observational studies have found quality child care to be a stronger predictor of positive outcomes for children exposed to more social risk during early childhood (Burchinal et al. 2006
; Burchinal, Peisner-Feinberg, Bryan, & Clifford, 2000
; Caughy, DiPietro, & Strobino, 1994
; Hubbs-Tait et al. 2002
; Peisner-Feinberg & Burchinal, 1997
; Peisner-Feinberg, Burchinal, Clifford, Culkin, Howes, Kagan, & Yazejian, 2001
; Schliecker, Whit, & Jacobs, 1991
; Vandell, 2004
). This sample, however, consisted of individuals all considered high risk due to poverty and most considered at high risk due to minority ethnic status. This homogeneity within the present sample could have precluded detection of the expected interaction between risk and treatment.
Some limitations should be considered in interpreting the findings of the study. First, the sample was limited to individuals born into low-income families almost all of whom were African American, and thus the findings generalize to that demographic group and may apply to other groups in unknown ways. As noted above, being of minority ethnic status is a variable that in and of itself has been found to be a risk factor. In addition to being more likely to be of low-income (Denavas-Walt, Proctor, & Lee, 2006
) and to experience other stressors that European-Americans (Evans, 2004
), discrimination and racism experienced by ethnic minority families may also negatively influence development (Murry, Brown, Brody, Cutrona, & Simons, 2001
; Prelow, Danoff-Burg, Swenson, & Pugliano, 2004
). That is, as Murry et al. (2001)
found, while a lack of income and other resources is a significant factor in families’ stress and functioning, “simply being Black in America” (p. 917) can also played a critical yet sometimes unacknowledged role affecting maternal psychological functioning, thus influencing the quality of relationships and interactions in the home environment.
A second caveat is that the sample size was small which may have reduced the power to detect smaller relationships and interaction effects (McClelland & Judd, 1993
). This may have been especially problematic when considering the data on illegal activity. The total sample size was relatively small, and the proportion of young adults who self-reported lawbreaking was smaller still. Admission of a misdemeanor occurred in only 17% of the sample, and only 10% admitted a felony. Power may also have been limited by the fact that most of the outcomes considered here were dichotomous rather than continuous variables.
Another limitation of this work, one generally shared by the literature in this area, is that some of the risk factors that may have contributed to outcomes were not assessed and thus were not included in the cumulative risk index. Within the literature on this topic, wide variety exists concerning this issue. For example, Brody, Kim, and Murry (2003)
included 7 possible factors; Sameroff et al. (1993)
had 10; while Evans (2003)
listed 9. This diversity among risk factors makes it difficult to compare findings across studies. An alternate approach to studying the question of risk might be to combine risk variables empirically using factor analyses as was done by Deater et al. (1998)
. Burchinal, Roberts, et al., (2000)
compared three approaches to analyzing risk – testing individual risk factors, creating risk-factor scores using factor analyses, and calculating a cumulative risk index – and found that similar, but not identical, conclusions could be drawn using each approach. Given sufficient sample sizes, considering domains of risk, rather than simply summing indicators, may be more appropriate for different outcomes. On the other hand, longitudinal studies often consist of small sample sizes, for which a cumulative risk index may be most appropriate (Burchinal, Roberts, et al., 2000
Similarly, the models in the current analyses did not include protective factors (beyond early educational intervention) that may have been related to outcomes, nor did they include how the adolescents and young adults interpreted the early risk factors. Future research could include these variables to gain a better understanding of the effects of early risk as well as pathways to competence in the context of adversity (Masten et al., 1999
Another caveat concerns generalizations that can be made about the effects of child care. Although the treatment took place in a full-time child care setting, the educational intervention was not typical of the early child care experience for most young children. Moreover, although the treatment and control groups differed by the fact that one received the systematic early treatment and the other did not, many children in the control group did experience out-of-home care before the age of 5. Different types were used by this group including relative care, family day care homes, and state-licensed center care, as determined by family circumstances. Thus, the group comparisons are between those who did and did not receive early educational intervention in a child care setting, not between those who did and did not experience out-of-home child care.
Despite the limitations, several strengths of this study increase confidence in the findings. These strengths include the study’s longitudinal nature which provided prospective data on early risk, and the very long span of time covered by the data collection, from birth to young adulthood. This permitted early risk to be summed across early childhood, capturing the natural variation that occurred within individual lives as experienced at the time. As noted by Gerard and Buehler (2004)
, one of the strengths of cumulative risk models is “their potential to capture the natural covariation of risk factors” (p. 1833). In addition, both the Abecedarian and CARE studies had low rates of attrition increasing investigator confidence in long-term outcomes. Confidence in the conclusions pertaining to early educational intervention is increased by the fact that both Abecedarian and CARE were randomized studies. This degree of experimental control allows for the interpretation of early treatment’s contribution to the outcomes with more confidence than would be possible in a naturalistic study where self-selection into treatment could have biased the findings.
These findings have implications for public policy makers considering how to allocate limited resources. Given that the effects of early cumulative risk can be very long-lasting, and impact important basic young adult outcomes, resources are needed to help protect high risk children from the effects of such multiple stressors. Increased early risk may have a particularly negative effect on some of the basic level accomplishments society requires for minimal self-sufficiency. Early intervention, on the other hand, moderated the effects of less optimal home environments on educational attainment and was promotive for the important outcomes of college attendance and obtaining skilled employment in this high-risk sample. These findings affirm the allocation of resources to provide early childhood programs for high risk children.